JPS62209232A - Disc brake pad preventing noise - Google Patents

Abstract

PURPOSE:To prevent occurrence of noise, by forming a flame-coated layer having a specific hardness on the rear metal surface of a pad to inhibit the growth of frictional vibration. CONSTITUTION:In a pad 2 in which a lining 4 is bonded to a rear metal 3, a soft metal such as aluminum, zinc, copper or the like is flame-coated on the outer surface of a lining 4 abuts against a pawl in a caliper 6 to form a flame-coated layer 10 having a hardness of HB20-70. Accordingly, when the pawl 6 of a caliper is pressed against the rear metal 3, the soft flame-coated layer 10 is present between the rear metal 3 and the pawl 6, and is suitably deformed so that they are satisfactorily made into close-contact with each other. Thereby it is possible to inhibit the growth of frictional vibration to prevent occurrence of noise.

Description

[Detailed Description of the Invention] A. Purpose of the Invention (Field of Industrial Application) This invention is an invention that can be used for automobile disc brakes to obtain a pad that can effectively prevent noise generation. In particular, the structure is such that noise can be prevented without using a shim plate.

(Prior Art) As schematically shown in FIG. 5, a disc brake has a rotor 1 that rotates in conjunction with the wheels of an automobile, and has linings 4.4 bonded to the back metal 3 of a pad 2 facing both sides of the rotor 1. The pad 2 is sandwiched between the claw 6 of the caliper 5 and the piston 7, and pressure oil is supplied from the oil guide port 9 to the cylinder 8 into which the piston 7 is fitted, and the piston 7 is pushed out. The pad 2 and the pad 2 on the left side of the figure in contact with the pawl 6 through the caliper 5 are pressed against both sides of the rotor 1, and the friction between the lining 4 and the rotor 1 brakes the wheel through the rotor l. It is.

However, a disc brake configured and operated in this manner may generate noise during braking. This noise is likely to occur when the braking force is weak, that is, when the force applied to the brake pedal is small.

The cause of this noise is that when the pedaling force is low, the caliper pawl 6,
It is believed that if the adhesion between the piston 7 and the back metal 3 of the pad is weak, the pad will vibrate and generate noise when frictional vibrations occur between the rotor and the lining during braking. If you press harder, this noise will subside.

The adhesion between the pawl 6 and the piston 7 and the back metal 3 of the pad is as follows:
The harder the materials of the two contacting members, the worse the problem.

Because of this property, as a means to prevent noise, a shim plate made by coating both sides of a steel plate with a thickness of about 0.4 m/m with rubber is used to connect the back plate 3, pawl 6, and piston 7. Attempts have been made to improve the adhesion of adjacent members such as the back plate, pawls, and pistons through the shim plate. In addition, a hard metal is thermally sprayed on the backing metal 3 to improve the adhesion between the claw and the piston, and an aluminum plate is bonded to the backing metal with a rubber adhesive, and the outer surface of the aluminum plate is also coated with a rubber adhesive. coating to improve adhesion with pistons, etc. (Japanese Patent Laid-Open No. 50-1
12668 (described in Japanese Utility Model Publication No. 12668), and one which attempts to improve adhesion by coating the entire surface of the pad with a coating film with a high zinc content (described in Japanese Utility Model Application Publication No. 59-108832).

(Problems to be Solved by the Invention) However, among the above-mentioned means, thermal spraying of hard metal is not effective in preventing noise, and other means are effective in improving the adhesion between adjacent members. Although this method was effective, it had the disadvantage that it lacked durability and began to generate noise at an early stage.

In other words, rubber coatings, rubber-based adhesives, zinc-containing coatings, etc. improve adhesion between adjacent parts and prevent noise generation when new, but they quickly lose this effect. .

According to the research conducted by the present inventors, the noise prevention effect of the shim is as follows:
It has been found that increasing the adhesion between the back plate, caliper pawls, and piston suppresses pad vibration and prevents frictional vibrations from growing even during low pedal force braking, which tends to generate noise.

To measure the degree of adhesion, there is a method of determining the contact resonance frequency of the contact portion by compliance measurement.

When using the shim plate and when not using it, the fluid pressure supplied to the disc brake is @5 kg/corresponding to the pedal force.
crn”, and the differences as shown in the following table were observed.

This shows that the use of the shim plate significantly improves adhesion.

As mentioned above, interposing a rubber-coated steel shim plate between the back plate, pawl, and piston had a great noise prevention effect in the initial installation, but the reason for this was that the rubber coating It was thought that it had vibration damping properties. However, when the inventors investigated the vibration damping properties of pads and shims, the results shown in the table below were obtained. According to this, since the damping rate of the pad itself is 5 to 10 times larger than that of the shim plate, it can be inferred that the noise prevention effect is obtained by factors other than the vibration damping rate.

Therefore, the present invention was obtained as a result of searching for a means to prevent noise by using the pad itself without using a shim plate.

(Means for Solving the Problems) This invention involves spraying a soft metal with a hardness of HB20 to HB70 on the surface of the backing metal of the pad that comes into contact with one of the caliper pawls and the piston to form an anti-sprayed layer. It constitutes a disc brake pad that prevents noise.

In yet another embodiment, a heat-resistant resin coating is applied on the sprayed layer to form a disc brake pad that prevents noise.

(Function) As shown in Fig. 1, in the pad 2 formed by bonding the lining 4 to the back metal 3, aluminum, zinc, copper, etc. The hardness is HB20~ by thermal spraying soft metal.
70, so when the caliper pawl 6 (or piston 7) is pressed against the backing metal 3, the soft thermal spraying layer 10 will close between the backing metal 3 and the pawl 6 (or piston 7). The backing metal 3, pawl 6 (piston 7)
) will be in good contact with each other, preventing the growth of frictional vibrations and noise generation.

If the soft metal such as aluminum that forms the thermal spray layer 10 is too soft, it will elongate too much, which is a problem.
A hardness of ~70 is suitable.

This soft metal exhibits its anti-vibration effect only after repeated pressure friction from the caliper pawls and pistons causes the surface of contact between these and the sprayed metal to become familiar. However, if a coating 11 of heat-resistant resin such as silicone rubber or fluorine rubber is placed on top of the thermal spray layer 10 as shown in Figure 2, the coating will have a good effect from the initial stage due to the backing effect of this coating. You can get a deep youthfulness.

A sprayed layer 10 on the backing metal or a coating 11 thereon
When the caliper pawl 6 or the piston 7 is pressed against this, the soft metal thermal spray layer 10 or the thermal spray layer 10 and the coating 11 bulge on both sides of the pawl 6, as shown in FIG. A grip effect is produced to suppress the piston 7 from the side, and the vibration prevention effect can be enhanced in addition to adhesion.

On the other hand, even if the pawl 6 and piston 7 are coated with a soft metal spray layer or a heat-resistant synthetic resin coating, the bulge will remain at the 4th point.
As shown in the figure, no gripping effect is produced, so a large noise prevention effect cannot be obtained.

C Effects of the invention (1) Thermal sprayed layer 10 or thermal sprayed layer 10 and coating 11
Therefore, the adhesion between the back plate 3 and the caliper pawl 6 or the piston 7 is good, and the effect of preventing noise is great.

(2) Since the thermal sprayed layer 10 is made of soft metal and is durable, this noise prevention effect is highly durable.

(3) By applying the coating 11 to the sprayed layer 10, the noise prevention effect can be obtained from the beginning of use of the disc brake without waiting for the sprayed layer 10 to become familiar with the caliper pawls 6 and piston 7.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view of the pad taken along the line A-A in Fig. 5, showing a state in which a thermal sprayed layer has been applied to the back metal according to the present invention, and Fig. 2 is a similar sectional view showing a state in which a further coating has been applied to the pad. Figure 3 is a similar cross-sectional view showing the grip effect of the thermally sprayed layer, Figure 4 is a similar cross-sectional view showing the deformation when the thermally sprayed layer is formed on the pawl, and Figure 5 is a similar cross-sectional view of a normal disc brake. FIG. 2 is a side view showing a schematic configuration. 1: Rotor, 2: Pad, 3: Back metal, 4 Ni lining,
5: Caliper, 6: Pawl, 7: Piston, 8 Niji cylinder,
9: Oil filler port, 10: Thermal spray layer, 11: Coating. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1) The contact surface of the back metal (3) of the pad (2) that contacts one of the caliper pawl (6) and the piston (7) has a hardness of HB.
A disc brake pad for preventing noise, characterized in that a thermal spray layer (10) is formed by thermally spraying a soft metal of 20 to 70%. 2) A disc brake pad for preventing noise according to claim 1, wherein a heat-resistant resin coating (11) is applied on the thermal spray layer (10).